Ed the o-ring in your pic #1 is not on my NOS
one (see pic) and I don't see the purpose of it on yours. The Bolens PS units on the L.F.'s I believe are unlike what other mfg's did in the use of the control valve and the cylinder as a one piece unit, most use the valve on the steering column actuating flow, Bolens has a Cessna valve married to the hydraulic cylinder and the valve (on the later LF's) is actuated by the drag link, on the early models like yours it doesn't, so it has to have something to allow a " neutral" position and flow , then as you turn the steering wheel it pushes or pulls on the cylinder rod and you get the flow operating the cylinder. As you look at yours (in your pics ) where the hoses connect to the unit is the control valve.
I've never had one apart so I'm sorry I can't help you there, this valve may be spring loaded , pure speculation on my behalf but if you look at my pic #4 it's a later model PS with the larger Cessna valve and is spring loaded to return the spool into the center position ( pic #5 ) the spring is compressed to desired resistance by threading the nose piece on (pic #6)
The early models had a proportioning valve (pic #7) so the hydraulic fluid was able to flow to the dash mounted hydraulic control valves and the PS unit equally so the use of one didn't affect the operation of the other (in theory, again speculation).
The later model PS units design was routing the hydraulic flow from the pump to the PS valve first then to the lift control/auxiliary control valve then back to pump. Again speculating but thus the need for a larger valve and a return to "neutral" on the valve when not in use. I've rebuilt several of the later model PS units and most are froze in the neutral/center position , your hydraulics work but your stroking the cylinder with out any hydraulic flow.
There has to be a spool in your valve with o-rings to seal the flow when stroked in opposite directions. My guess is upon disassembly you will find them in their respective places inside the valve body itself once the spool is removed. Where is yours leaking from the valve or the rod side of the cylinder?
As mentioned a good hydraulic shop should be able to match up what you have o-rings and back up washers if used internally.
I believe (my pic #3) are the holes for a spanner wrench to loosen/tighten the cylinder from the valve, it would be my starting point.
Curious as the late model has a full disassembly diagram with individual pieces listed by part numbers or a rebuild kit, unfortunately it looks like one is not available for your early model, I do have the original instructions from the NOS
one and will dig them out to see if they may be of help. Sorry I couldn't of been more help to you. Good luck as you do what many of us have and use the necessity of the repair be your learning tool . As a reminder wear safety glasses upon the disassembly and reassembly process ,spring and perhaps spring loaded projectiles may await .
Edited by WrenchinOnIt, July 25, 2016 - 08:06 AM.